96 



BOTANY. 



has been applied (Fig, 81). These are composed of single- 

 cells, which have very thin and delicate walls (Fig. 82), and 

 are the active agents in the absorption of nutritive matters. 

 for the plant. 



Fig. 82. — Root-hairB of a eeedling rye plant. A, the ends of three hairs, one much 

 EimalTer th-iii the others ; the larger ones have particles of sand adhering to and im- 

 bedded in their walls ; B, the base of a hair growing from the rooi-cell, r. X 900. 



129. — In the development of the hairs on aerial parts of 

 plants it frequently happens that the terminal cell becomes; 

 changed into a secreting cell, in which gummy, resinous, or 

 other substances are produced ; sometimes several terminal' 



